In a power transmission system, employing a superconducting cable, such configuration that assures a facilitated laying-down operation and that operates as measures against heat intrusion has been proposed in Patent Literatures 1 and 2, as examples, by Satarou Yamaguchi, one of the present inventors.
Patent Literature 1 shows a configuration including a first pipe, within which a superconducting cable is housed, and a second pipe of a ferromagnetic material, disposed on an outer side of the first pipe. In the disclosed configuration, an end part(s) of a straight-shaped pipe section of the superconducting cable is connected by a bellows pipe, and the first pipe includes the bellows pipe.
Patent Literature 2 shows a superconducting power transmission cable at least including a first pipe, within which a superconducting conductor part is disposed, and a second pipe arranged on the outer side of the first pipe. A vacuum thermally insulating section is provided between the first and second pipes. A first pipe support ring that bears against an outer wall section of the first pipe is also provided between the first and second pipes, and a second pipe support ring is fitted on the inner wall section side of the second pipe. A support member is arranged between the first and second pipe support rings. FIG. 6 shows a configuration of a thermally insulated double-shell pipe. A cooling medium passage section 11, a superconducting conductor section 12 and an electrical insulation section 13 are provided in the superconducting conductor part which is housed within the first pipe 15 (see FIG. 6). The term “double-shell pipe” is termed herein as “double pipe”.